When I look to the stars, how far back am I seeing? © Getty Images

When I look to the stars, how far back am I seeing?

Stars are like your very own sparkly, astronomical time machine, taking you back thousands of years.

Asked by: Dr Paul Barker, Bournemouth

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All of the stars you can see with the unaided eye lie within about 4,000 light-years of us. So, at most, you are seeing stars as they appeared 4,000 years ago.

All of these stars will die at some point, and astronomers have estimated that the death rate for visible stars in our Milky Way is around one star every 10,000 years. So given that we can only see 4,000 years back in time, it is unlikely (though not impossible) that any of them have died yet.

In other words, choose any star in the night sky, and the chances are that you could visit it today (if you had a fast enough spaceship).

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